https://www.paypal-community.com/t5/forums/postpage/board-id/SecurityandFraud?message-subject=Fraud#

[Timobarty]

I sold an item on Discogs. Buyer paid for item. I sent item. Whilst item was in transit a claim was put in saying someone had used their account to buy item… PayPal, through laziness, ignorance and incompetence, decided in their favour. I’m now out of pocket. How do I appeal this abysmal decision. Used to think PayPal was secure and thorough but clearly not. Have also had to pay £12 for them to give the cheating buyer my money. I suspect a scam, PayPal is clueless

[kernowlass]

@Timobarty 

If you were charged £12 then it was a chargeback done via the buyers credit card and not a paypal dispute.

With a chargeback the card company makes all decisions and all paypal can do is pass on any information on your behalf.

The fee is the credit card companies fee not paypals.

If the transaction is protected by Seller Protection Policy, PayPal will cover the amount of the chargeback and waive the chargeback fee. You can view the chargeback fee and process in our  User Agreement.

So your best bet is to read up on paypals seller protection policy to see where you missed out as it is not a 100% guarantee to protect you for everything.